【原】C# 简单实现QQ截图功能

Csharp小记 2023-10-29 发布于江苏

展开全文

接上一篇写的截取电脑屏幕，我们在原来的基础上加一个选择区域的功能，实现自定义选择截图。

个人比较懒，上一篇的代码就不重新设计了，就简单改一下呈现方式。

不得不吐槽一下，在windows10系统上设置了放大比例的话，用这种方式来实现截图功能的话需要去计算比例。后面有机会的话，用第三方DLL再实现一次。

实现功能：

屏幕选择区域截图

开发环境：

开发工具：Visual Studio 2013

.NET Framework版本：4.5

实现代码：

//将上一篇的内容改成以下内容// pictureBox1.Image = bmp;Form2 frm = new Form2();frm.BaseImage = bmp;frm.TopMost = true;frm.Show();

/*Form2代码*/#region Dll引用[DllImport("User32.dll", EntryPoint = "GetDC")]private extern static IntPtr GetDC(IntPtr hWnd);
[DllImport("User32.dll", EntryPoint = "ReleaseDC")]private extern static int ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("gdi32.dll")]public static extern int GetDeviceCaps(IntPtr hdc, int nIndex);
[DllImport("User32.dll")]public static extern int GetSystemMetrics(int hWnd);
const int DESKTOPVERTRES = 117;const int DESKTOPHORZRES = 118;
const int SM_CXSCREEN = 0;const int SM_CYSCREEN = 1;
#endregion
//<summary>//获取DPI缩放比例//</summary>//<param name="dpiscalex"></param>//<param name="dpiscaley"></param>public static void GetDPIScale(ref float dpiscalex, ref float dpiscaley){    int x = GetSystemMetrics(SM_CXSCREEN);    int y = GetSystemMetrics(SM_CYSCREEN);    IntPtr hdc = GetDC(IntPtr.Zero);    int w = GetDeviceCaps(hdc, DESKTOPHORZRES);    int h = GetDeviceCaps(hdc, DESKTOPVERTRES);    ReleaseDC(IntPtr.Zero, hdc);    dpiscalex = (float)w / x;    dpiscaley = (float)h / y;}

public Bitmap BaseImage { get; set; }
Graphics picGraphics;//记录鼠标开始截图的位置int startX = 0, startY = 0;//记录鼠标结束截图的位置int endX = 0, endY = 0;//记录DPI缩放比例float x = 0f, y = 0f;public Form2(){    InitializeComponent();}private void Form2_Load(object sender, EventArgs e){    /* 初始化赋值*/
    GetDPIScale(ref x, ref y);    picGraphics = pictureBox1.CreateGraphics();}
private void pictureBox1_Paint(object sender, PaintEventArgs e){    DrawRect(endX - startX, endY - startY,e.Graphics);}
private void Form2_KeyPress(object sender, KeyPressEventArgs e){    //按下esc退出    if (e.KeyChar == 27)    {        this.Close();    }}
//完成截图private void lbSucess_Click(object sender, EventArgs e){    int clip_w = (int)((endX - startX) * x) - 4, clip_h = (int)((endY - startY) * y) - 4;    if (clip_w < 1 || clip_h < 1)    {        return;    }    //获取截图    Bitmap clipBmp = new Bitmap(clip_w, clip_h);    Graphics g = Graphics.FromImage(clipBmp);    g.CopyFromScreen((int)(startX * x) + 2, (int)(startY * y) + 2, 0, 0, new Size(clip_w, clip_h), CopyPixelOperation.SourceCopy);    //将截图设置到剪切板    Clipboard.SetImage(clipBmp);    g.Dispose();    this.Close();}
private void pictureBox1_MouseDown(object sender, MouseEventArgs e){    //隐藏操作面板    panel1.Visible = false;    //记录鼠标开始截图的位置    if (e.Button == MouseButtons.Left)    {        startX = e.X;        startY = e.Y;        endX = 0; endY = 0;    }}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e){    if (e.Button == MouseButtons.Left)    {        //绘制截图区域        DrawRect(e.X - startX, e.Y - startY, picGraphics);    }}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e){    //截图完成    if (e.Button == MouseButtons.Left)    {        endX = e.X;        endY = e.Y;
        DrawRect(endX - startX, endY - startY, picGraphics);        if (endX > startX && endY > startY)        {            //显示操作面板            Thread.Sleep(100);            panel1.Location = new Point(e.X - panel1.Width, e.Y + 5);            panel1.Visible = true;                   }    }}
//绘制截图区域private void DrawRect(int w, int h,Graphics g){    Bitmap img = (Bitmap)BaseImage.Clone();
    //双缓冲技术画矩形,防止重影和抖动    Graphics Painter = Graphics.FromImage(img);    Painter.DrawRectangle(new Pen(Color.Red), startX * x, startY * y, w * x, h * y);    g.DrawImage(img, 0, 0, img.Width / x, img.Height / y);
    Painter.Dispose();    img.Dispose();}